Die-attach machines are commonly used in semiconductor package manufacturing to accurately transfer semiconductor components to semiconductor substrates. For instance, a die bonder has a die-delivery head for transferring semiconductor dice from a wafer table to a leadframe in a pick-and-place operation. However, there is a limitation in the throughput of die-bonding processes—normally quantified in terms of ‘Units per Hour’ (UPH)—attainable by die bonders with a single bond head.
One way of increasing the UPH of such die bonders is by constructing a system of cascading die bonders. FIG. 1 shows a system 100 constructed by connecting two die bonders 102, 104 together. The system 100 comprises wafer tables 106, 108 for placing a wafer containing singulated semiconductor dice 107, support devices 110, 112 for conveying leadframes 109, 111 along an X-direction, and die-delivery devices 114, 116 having respective die-delivery heads 118, 120 for transferring the semiconductor dice 107 from the wafer tables 106, 108 to bonding locations of the leadframes 109, 111 along a Y-direction orthogonal to the X-direction. A conveying device 122 is further arranged between the two die bonders 102, 104 for transferring the leadframes 109, 111 from an offload section of the leftmost die bonder 102 to an onload section of the rightmost die bonder 104.
If other support devices 110, 112 having larger widths are used to support leadframes with corresponding larger leadframe widths, the distance travelled by the die-delivery heads 118, 120 from the wafer tables 106, 108 to the outermost edges of the leadframes along the Y-direction would be increased. This accordingly reduces the UPH of the system 100.
In addition, a large footprint is typically required to construct the system 100 which comprises two separate die bonders 102, 104 connected via the intervening conveying device 122. Thus, construction of the system 100 takes up valuable space in a factory.
Furthermore, the system 100 of cascading die bonders 102, 104 means that it has twice as many devices as that of a single die bonder. Accordingly, the probability of any one of the devices malfunctioning in the system 100 will be higher than that of a single die bonder. As the die bonders 102, 104 perform die-bonding in a sequential manner within the system 100, a malfunction of any one of the die bonders 102, 104 invariably causes an operational halt of the entire system 100, thereby affecting its UPH.
It is therefore an object of this invention to ameliorate any one of the above limitations of such systems 100 comprising cascading die bonders 102, 104.